Microsoft Security Bulletin MS07-062 - Important

Vulnerability in DNS Could Allow Spoofing (941672)

General Information

Executive Summary

This important security update resolves a privately reported vulnerability. This spoofing vulnerability exists in Windows DNS Servers and could allow an attacker to send specially crafted responses to DNS requests, thereby spoofing or redirecting Internet traffic from legitimate locations.

This is an important security update for all supported editions of Microsoft Windows 2000 Server and Windows Server 2003. For more information, see the subsection, Affected and Non-Affected Software, in this section.

This security update addresses the vulnerability by increasing the randomness of DNS transaction IDs. For more information about the vulnerability, see the Frequently Asked Questions (FAQ) subsection for the specific vulnerability entry under the next section, Vulnerability Information.

Recommendation: Microsoft recommends that customers apply the update at the earliest opportunity.

Known Issues: None

Affected and Non-Affected Software

The software listed here has been tested to determine which versions or editions are affected. Other versions or editions are either past their support life cycle or are not affected. To determine the support life cycle for your software version or edition, visit Microsoft Support Lifecycle.

I am using an older version or edition of the software discussed in this security bulletin. What should I do?The affected software listed in this bulletin has been tested to determine which versions or editions are affected. Other versions and editions are past their support life cycle. To determine the support life cycle for your product and version, visit Microsoft Support Lifecycle.

It should be a priority for customers who have older versions or editions of the software to migrate to supported versions to prevent potential exposure to vulnerabilities. For more information about the Windows Product Lifecycle, visit the following Microsoft Support Lifecycle. For more information about the extended security update support period for these operating system versions, visit the Microsoft Product Support Services Web site.

Customers who require custom support for older software must contact their Microsoft account team representative, their Technical Account Manager, or the appropriate Microsoft partner representative for custom support options. Customers without an Alliance, Premier, or Authorized Contract can contact their local Microsoft sales office. For contact information, visit the Microsoft Worldwide Information Web site, select the country, and then click Go to see a list of telephone numbers. When you call, ask to speak with the local Premier Support sales manager. For more information, see the Windows Operating System Product Support Lifecycle FAQ.

Mitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of a vulnerability. Microsoft has not identified any mitigations for this vulnerability.

Workarounds for DNS Spoofing Attack Vulnerability – CVE-2007-3898

Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has not identified any workarounds for this vulnerability.

FAQ for DNS Spoofing Attack Vulnerability – CVE-2007-3898

What is the scope of the vulnerability? A spoofing vulnerability exists in Windows DNS Severs. An attacker who successfully exploited this vulnerability could impersonate a legitimate address.

What causes the vulnerability? The Windows DNS Server service doesn’t provide enough entropy in its random choice of transaction values when it sends out queries to upstream DNS servers.

What might an attacker use the vulnerability to do? An attacker who successfully exploited this vulnerability could gain information about the DNS server’s transaction IDs, and use that information to send malicious responses to DNS requests, thus redirecting Internet traffic from legitimate locations to an address of the attacker’s choice.

How could an attacker exploit the vulnerability? An attacker who successfully exploited this vulnerability could respond to a DNS query with false or misleading information, thereby redirecting Internet traffic from legitimate locations.

Could the vulnerability be exploited over the Internet? Yes, an attacker could exploit this vulnerability over the Internet by sending specific responses to an Internet-facing DNS server that is performing recursive lookups.

What systems are primarily at risk from the vulnerability? This vulnerability applies to Windows DNS servers that perform recursive lookups. For more information on recursive queries, please refer to the Technet article on How DNS query works.

What does the update do? The update removes this vulnerability by increasing the randomness of the transaction IDs in recursive DNS server communications.

When this security bulletin was issued, had this vulnerability been publicly disclosed? No. Microsoft received information about this vulnerability through responsible disclosure.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited? No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers and had not seen any examples of proof of concept code published when this security bulletin was originally issued.

Finally, security updates can be downloaded from the Microsoft Update Catalog. The Microsoft Update Catalog provides a searchable catalog of content made available through Windows Update and Microsoft Update, including security updates, drivers and service packs. By searching using the security bulletin number (such as, “MS07-036”), you can add all of the applicable updates to your basket (including different languages for an update), and download to the folder of your choosing. For more information about the Microsoft Update Catalog, see the Microsoft Update Catalog FAQ.

Detection and Deployment Guidance

Microsoft has provided detection and deployment guidance for this month’s security updates. This guidance will also help IT professionals understand how they can use various tools to help deploy the security update, such as Windows Update, Microsoft Update, Office Update, the Microsoft Baseline Security Analyzer (MBSA), the Office Detection Tool, Microsoft Systems Management Server (SMS), and the Extended Security Update Inventory Tool. For more information, see Microsoft Knowledge Base Article 910723.

Microsoft Baseline Security Analyzer

Microsoft Baseline Security Analyzer (MBSA) allows administrators to scan local and remote systems for missing security updates as well as common security misconfigurations. For more information about MBSA, visit Microsoft Baseline Security Analyzer.

The following table provides the MBSA detection summary for this security update.

File Information

The English version of this security update has the file attributes that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.

For all supported editions of Microsoft Windows 2000 Server Service Pack 4:

Unattended Setup mode. No user interaction is required, but installation status is displayed. If a restart is required at the end of Setup, a dialog box will be presented to the user with a timer warning that the computer will restart in 30 seconds.

/quiet

Quiet mode. This is the same as unattended mode, but no status or error messages are displayed.

Restart Options

/norestart

Does not restart when installation has completed

/forcerestart

Restarts the computer after installation and force other applications to close at shutdown without saving open files first.

/warnrestart[:x]

Presents a dialog box with a timer warning the user that the computer will restart in x seconds. (The default setting is 30 seconds.) Intended for use with the /quiet switch or the /passive switch.

/promptrestart

Display a dialog box prompting the local user to allow a restart

Special Options

/overwriteoem

Overwrites OEM files without prompting

/nobackup

Does not back up files needed for uninstall

/forceappsclose

Forces other programs to close when the computer shuts down

/log:path

Allows the redirection of installation log files

/extract[:path]

Extracts files without starting the Setup program

/ER

Enables extended error reporting

/verbose

Enables verbose logging. During installation, creates %Windir%\CabBuild.log. This log details the files that are copied. Using this switch may cause the installation to proceed more slowly.

Note You can combine these switches into one command. For backward compatibility, the security update also supports the setup switches that the earlier version of the Setup program uses. For more information about the supported installation switches, see Microsoft Knowledge Base Article 262841. For more information about the Update.exe installer, visit the Microsoft TechNet Web site.

Removing the Update

This security update supports the following setup switches.

Supported Spuninst.exe Switches

Switch

Description

/help

Displays the command-line options

Setup Modes

/passive

Unattended Setup mode. No user interaction is required, but installation status is displayed. If a restart is required at the end of Setup, a dialog box will be presented to the user with a timer warning that the computer will restart in 30 seconds.

/quiet

Quiet mode. This is the same as unattended mode, but no status or error messages are displayed.

Restart Options

/norestart

Does not restart when installation has completed

/forcerestart

Restarts the computer after installation and force other applications to close at shutdown without saving open files first.

/warnrestart[:x]

Presents a dialog box with a timer warning the user that the computer will restart in x seconds. (The default setting is 30 seconds.) Intended for use with the /quiet switch or the /passive switch.

/promptrestart

Display a dialog box prompting the local user to allow a restart

Special Options

/forceappsclose

Forces other programs to close when the computer shuts down

/log:path

Allows the redirection of installation log files

Verifying That the Update Has Been Applied

Microsoft Baseline Security Analyzer

To verify that a security update has been applied to an affected system, you may be able to use the Microsoft Baseline Security Analyzer (MBSA) tool. See the section, Detection and Deployment Tools and Guidance, earlier in this bulletin for more information.

File Version Verification

Because there are several versions of Microsoft Windows, the following steps may be different on your computer. If they are, see your product documentation to complete these steps.

Click Start, and then click Search.

In the Search Results pane, click All files and folders under Search Companion.

In the All or part of the file name box, type a file name from the appropriate file information table, and then click Search.

In the list of files, right-click a file name from the appropriate file information table, and then click Properties.

Note Depending on the version of the operating system or programs installed, some of the files that are listed in the file information table may not be installed.

On the Version tab, determine the version of the file that is installed on your computer by comparing it to the version that is documented in the appropriate file information table.

Note Attributes other than the file version may change during installation. Comparing other file attributes to the information in the file information table is not a supported method of verifying that the update has been applied. Also, in certain cases, files may be renamed during installation. If the file or version information is not present, use one of the other available methods to verify update installation.

Registry Key Verification

You may also be able to verify the files that this security update has installed by reviewing the registry keys listed in the Reference Table in this section.

These registry keys may not contain a complete list of installed files. Also, these registry keys may not be created correctly when an administrator or an OEM integrates or slipstreams this security update into the Windows installation source files.

Microsoft Windows Server 2003 (all editions)

Reference Table

The following table contains the security update information for this software. You can find additional information in the subsection, Deployment Information, in this section.

Inclusion in Future Service Packs

The update for this issue may be included in a future update rollup

Deployment

Installing without user intervention

For all supported 32-bit editions of Windows Server 2003:

Windowsserver2003-kb941672-x86-enu /quiet

For all supported Itanium-based editions of Windows Server 2003:

WindowsServer2003-KB941672-ia64-enu /quiet

For all supported x64-based editions of Windows Server 2003:

WindowsServer2003.WindowsXP-KB941672-x64-enu /quiet

Installing without restarting

For all supported 32-bit editions of Windows Server 2003:

Windowsserver2003-kb941672-x86-enu /norestart

For all supported Itanium-based editions of Windows Server 2003:

WindowsServer2003-KB941672-ia64-enu /norestart

For all supported x64-based editions of Windows Server 2003:

WindowsServer2003.WindowsXP-KB941672-x64-enu /norestart

Further information

See the subsection, Microsoft Detection and Deployment Tools and Guidance

Update Log File

KB941672.log

Restart Requirement

Restart required

Yes, you must restart your system after you apply this security update. See Restart Note below for more information.

Restart Note: A system restart can be avoided for Windows Server 2003 by stopping the DNS service, installing the update, and then restarting the DNS service. If the DNS service is not stopped before installing the update, then a system restart will still be required.

File Information

The English version of this security update has the file attributes that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.

Unattended Setup mode. No user interaction is required, but installation status is displayed. If a restart is required at the end of Setup, a dialog box will be presented to the user with a timer warning that the computer will restart in 30 seconds.

/quiet

Quiet mode. This is the same as unattended mode, but no status or error messages are displayed.

Restart Options

/norestart

Does not restart when installation has completed

/forcerestart

Restarts the computer after installation and force other applications to close at shutdown without saving open files first.

/warnrestart[:x]

Presents a dialog box with a timer warning the user that the computer will restart in x seconds. (The default setting is 30 seconds.) Intended for use with the /quiet switch or the /passive switch.

/promptrestart

Display a dialog box prompting the local user to allow a restart

Special Options

/overwriteoem

Overwrites OEM files without prompting

/nobackup

Does not back up files needed for uninstall

/forceappsclose

Forces other programs to close when the computer shuts down

/log:path

Allows the redirection of installation log files

/integrate:path

Integrates the update into the Windows source files. These files are located at the path that is specified in the switch.

/extract[:path]

Extracts files without starting the Setup program

/ER

Enables extended error reporting

/verbose

Enables verbose logging. During installation, creates %Windir%\CabBuild.log. This log details the files that are copied. Using this switch may cause the installation to proceed more slowly.

Note You can combine these switches into one command. For backward compatibility, the security update also supports many of the setup switches that the earlier version of the Setup program uses. For more information about the supported installation switches, see Microsoft Knowledge Base Article 262841. For more information about the Update.exe installer, visit the Microsoft TechNet Web site.

Removing the Update

This security update supports the following setup switches.

Supported Spuninst.exe Switches

Switch

Description

/help

Displays the command-line options

Setup Modes

/passive

Unattended Setup mode. No user interaction is required, but installation status is displayed. If a restart is required at the end of Setup, a dialog box will be presented to the user with a timer warning that the computer will restart in 30 seconds.

/quiet

Quiet mode. This is the same as unattended mode, but no status or error messages are displayed.

Restart Options

/norestart

Does not restart when installation has completed

/forcerestart

Restarts the computer after installation and force other applications to close at shutdown without saving open files first.

/warnrestart[:x]

Presents a dialog box with a timer warning the user that the computer will restart in x seconds. (The default setting is 30 seconds.) Intended for use with the /quiet switch or the /passive switch.

/promptrestart

Display a dialog box prompting the local user to allow a restart

Special Options

/forceappsclose

Forces other programs to close when the computer shuts down

/log:path

Allows the redirection of installation log files

Verifying that the Update Has Been Applied

Microsoft Baseline Security Analyzer

To verify that a security update has been applied to an affected system, you may be able to use the Microsoft Baseline Security Analyzer (MBSA) tool. See the section, Detection and Deployment Tools and Guidance, earlier in this bulletin for more information.

File Version Verification

Because there are several versions of Microsoft Windows, the following steps may be different on your computer. If they are, see your product documentation to complete these steps.

Click Start, and then click Search.

In the Search Results pane, click All files and folders under Search Companion.

In the All or part of the file name box, type a file name from the appropriate file information table, and then click Search.

In the list of files, right-click a file name from the appropriate file information table, and then click Properties.

Note Depending on the version of the operating system or programs installed, some of the files that are listed in the file information table may not be installed.

On the Version tab, determine the version of the file that is installed on your computer by comparing it to the version that is documented in the appropriate file information table.

Note Attributes other than the file version may change during installation. Comparing other file attributes to the information in the file information table is not a supported method of verifying that the update has been applied. Also, in certain cases, files may be renamed during installation. If the file or version information is not present, use one of the other available methods to verify update installation.

Registry Key Verification

You may also be able to verify the files that this security update has installed by reviewing the registry keys listed in the Reference Table in this section.

These registry keys may not contain a complete list of installed files. Also, these registry keys may not be created correctly when an administrator or an OEM integrates or slipstreams this security update into the Windows installation source files.

Other Information

Acknowledgments

Microsoft thanks the following for working with us to help protect customers:

Support

Customers in the U.S. and Canada can receive technical support from Microsoft Product Support Services at 1-866-PCSAFETY. There is no charge for support calls that are associated with security updates.

International customers can receive support from their local Microsoft subsidiaries. There is no charge for support that is associated with security updates. For more information about how to contact Microsoft for support issues, visit the International Support Web site.

Disclaimer

The information provided in the Microsoft Knowledge Base is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.